Door operator



Feb. 6, 1945. J, R. NEWKIRK DOOR OPERATOR Filed 001;. 29, 1943 2Sheets-Sheet 1 INVENTOR. John R-NzwKlr-K- Feb. 6, 1945. J NEwKlRK2,368,722

DOOR OPERATOR Filed Oct. 29, 1943 2 Sheets-Sheet 2 INVENTOR. John R- NewKirk.

BY (A Patented Feb. 6, 1945 UNITED STATES PATENT OFF-ICE noonorl'n'a'roa John a. Newkirh, Railway, N. 1., asaignor to NationalPneumatic Company, New York, N. Y., a corporation of West VirginiaApplication October 29, 1943, Serial No. 508,195

3Claims.

This invention relates to power operated doors and is particularlyadapted for use on doors which are diiilcult to start open for anyreason.

- The main object of this invention is to provide .as an additionthereto and an improvement -thereon of means for holding a door open ina system of the type disclosed and claimed in my copending applicationSerial No. 481,107, filed March 30, 1943 for "Door operator, and nowUnited States Patent No. 2,343,316, issued March '1, 1944.

The generaloblect of this invention is to provide with a power dooroperator arranged and constructed so as to automatically break the dooropen a short distance as an incident to the normal actof opening thedoor, means for holding the door open as long as may be desired.

Other and more detailed objects of this invention will be apparent fromthe following descripton of one embodiment thereof as made in connectionwith the attached drawings.

This invention resides substantially in the combination, construction,arrangement and relative location of parts, all as will be described indetail below.

In the accompanying drawings,

Figure 1 is a diagrammatic and schematic front elevational view of adoor in combination with the operator of this invention;

Figure 2 is a longitudinal, central, cross-sectional view through thedoor engine used in the combination of this invention;

Figure 3 is a similar view of the gear train mechanism interconnectingthe engine with the door operating levers; and

Figure 4 is a horizontal cross-sectional view through the door framewith some parts broken away showing the mechanism for holding the dooropen.

Doors for use in many places are frequently so heavy or are employedunder such conditions that persons wishing to pass through the doorwayfind it dimcult to get the door started in its opening movement. Forexample, the end doors of railway vehicles which are air conditioned areoften diillcult to open for one or more of several frequentlyencountered conditions. In the first place, these doors are relativelymassive and heavy requiring considerable eifort to start them in theiropening movement. In the next place, passengers are commonly-in the actof opening the door during the deceleration of the train, making itnecessary to overcome the inertial resistance of the door to openingwhile the train is decelerating. Finally, the air conditioned railwaycars frequently have a slightly greater than atmospheric pressurecondition in the interior thereof which iurther adds to the diilicultyof "breaking" the door open. In accordance with this invention a poweroperating device is arranged so that as an incident to the act ofstarting the door open, the power operator for closins the door suppliesfor a short interval of time sufllcient power to start the door openafter which it is relatively easy to complete its opening movement.-

The complete system herein disclosed results from the addition to anarrangement as above described and disclosed in my above mentionedcopending application, which includes means formechanically holding thedoor in full open position and for maintaining the door operating engineopen to exhaust, that is the same condition in which it is put at thetimeit breaks" the door open, as explained above.

Referring to Figure 1, a door is illustrated at I hingedly mounted at 2in the door opening. 1 As viewed in Figure 1 it is intended that thedoor open away from the side from which it is viewed in this figure.Mounted above the door on the adjacent frame is a diflerential airengine 3 having as a structural part a gear box or gear train 4. A shortvertical shaft 5 is connected to the gear box at one end and at theother end to a lever 6 which is pivotally connected to a lever l in turnpivotally attached to the door by means of a plate or bracket 8.Pressure fluid, such as compressed air is supplied from a, suitablesource, not shown, through a pipe I I having a control valve l2, an airstrainer l3 and a needle valve arrangement I! all of common and wellknown construction, to a valve Ill having a solenoid operator 9. Thisvalve in turn is connected by a pipe It to the end of the large cylinderof the diiierential engine. The magnet valve is very well known in thisart and is of the type disclosed in United States Patent No. 1,849,516at Figure 37. This is a so-called exhaust type of valve which, when-itssolenoid is de-energized, connects pipe H to pipe It to maintain thepressure in the cylinder of the engine. When the solenoid 9 isenergized, the valve it shifts to cut off the connection between pipesII and I6 and to open pipe it to exhaust.

One terminal of the solenoid winding is grounded'and the other isconnected by means of wire I! to a switch l8 mounted on the door, whichswitch is supplied through the other lead to the positive side of agrounded-current source, not shown.

Switch 18 is arranged on the door so as to be valve operator operated bya push plate I! which is pivotally mounted by means of'the plate 28 onthe door. This p sh plate, as illustrated, is frequently used in poweroperated doors and forms. The doorknob 2| on the other side of the .doorhas a shaft passing through the door and invention is shown in fulldetail in Figures 2 and.

3. It is a differential engine having a large cylinder 22 closed at oneend by a cap 25 which has a threaded port to which the pipe- I 5connects. The other end of the cylinder is provided with a reducingsleeve 21 internally threaded for attachment to the other end ofcylinder 22 and for at? tachment to one end of the smaller cylinder 28.The other end of the cylinder 28 is externally threaded to receive theinternally threaded end 30 of the gear housing 4.v Within the largercylinder 22 is a piston assembly comprising the head 32 and the integralcylindrical housing 33 of substantial diameter so as to render theopposite sides of the head of different effective areas. Secured to theother end of the housing 33 is attached a small piston 38 for thecylinder 28 which is secured to the housing by means ofa double endedstud bolt 34. This bolt has a coupling eye 35 by means of which it ispivotally connected to the rack member 50 in the gear housing 4. Thepiston 35 is provided with the usual cup washer or backing 31 of somesuitable flexible material. In a similar way a cup backing or washer 38of flexible material is clamped onto the piston head 32 by means of athreaded plug 39. The plug 39 has a large central passage in which isslidably mounted the tubular member 49 which has a central passage ofdifferent diameters to form a seat 42. A spring 4| lies within thehousing 33 and engages one end of the tubular member 40 to hold it inthe position shown in Figure 2.. A ball is arranged to engage the seat42 and a transverse pin 44 serves to limit the movement of the ball fromits seat. The smaller bore of the tubular member is provided with a tube45 which is threadedly secured therein and acts to hold a disc member 46on the tubular member and a suitable seat disc 41 therein made ofsuitable material. The valve thus formed is adapted to cooperate withthe seat 43 on the inner face of the cap 25. This cap has a passage 49opening into the large cylinder outside of the diameter of the valve 41and into the space defined by the seat 58 which is in communication withthe threaded port in the cap. The rack member 50 has a rack 5| upon oneface positioned to engage a gear 52 secured to the shaft 5 previouslymentioned. An idler roller 53 engages the opposite face of the rack tohold its teeth in engagement with the teeth of the gear 52.

b As is clear from Figure 1, the gear housing 4 is mounted on the end ofthe cylinder 28. The engine is provided with a clamp 23 having anattach-ment plate 24 by means of which the engine may be mounted.

The particularly novel feature of this invention is illustrated inFigures 1 and 4. Mounted on the wall framing the door opening in whichthe door I is mounted, is a device 54 comprising a mechanicalarrangement for holding the door open and a switch for controlling thesolenoid magnet 9. Mounted on the door on the may 888111116 many sidetowards which the door opens is what may 76 assays:

be termed a catch member 51. Mounted on the adjacent wall in a positionto become operatively associated with the catch member 51, is thecombined keeper and switch device 54. as diagrammatically illustrated inFigure 4. This device includes a suitable housing within which arepivotally mounted at a pair of arms 55, which are v51 enters at itspointed end between the free ends of levers 59, pushing them aside untilit reaches a point where the springs 5| can snap the levers 59 over thehead of the catch member 51. This device also includes a switch 58comprising a pair of flxed contacts and a movable contact positioned tobe engaged by the head of the catch member 51 so as to. be closed whenthe door is mechanically held in open position. The positive lead of thecurrent source is connected by wire 55 to one of the fixed contacts ofthe switch 58, while the other fixed contact is connected by wire 55 tothe wire I! going to the solenoid operator 9.

The operation of the device will now be described upon the assumptionthat th door is closed, solenoid 9 is de-energized, and the engine is inthe position shown in Figure 2 with air supplied to the left hand end ofthe large cylinder 22 by reason of the connection of pipe II to pipe itby valve In. It will be noted that no pressure fluid is supplieddirectly to thespace between the two pistons as in the usual case in theoperation of differential pressure fluid engines. However, the fluidpressure does enter this space by seeping around the piston cup 38. Itwill be noted that the creation of a pressure condition in the left handend of cylinder 22 will cause the application of fluid pressure to thepiston cup 38 from the left towards the right contrary to the manner inwhich pressure fluid is usually supplied to piston cups. The result isthat air, if it be the pressure fluid, can seep around the piston cup 38from the left to the right, during closing, to build up a balancedpressure condition in the chambers on opposite sides of the piston 32.It will be recalled that this is the normal condition of the apparatuswith the door closed. The air which is trapped between the pistons isforced into a smaller space during the completion of the closingmovement of the door and, therefore, cushions the final closing movementof the door to prevent slamming of it.

Should a person desire to go through the doorway from the side fromwhich Figure 1 is viewed, he will move up to the door and apply pressureto the push plate l9 which is a normal gesture of one wishing to open adoor which swings away from him in opening. A comparatively lightpressure will cause the push plate to move towards the door and closeswitch I 8. It may be noted that one approaching the door from the otherside would grasp the doorknob 2| and start to pull it to open the doorcausing the same movement of the push plate I 9. The closing of switchl8 completes the circuit of the solenoid 9 in an obvious manner whichoperates valve III to cut off pipe II from pipe l5 and connect pipe 5 tothe atmosphere. The left hand end of cylinder 22 of the engine is almostinstantaneously freed of all pressure fluid so that the pressure fluidto the right of the large piston becomes trapped. This is so as thetrapped pressure fluid will expand the piston cup 38 when the pressuredrops in the large cylinder. The removal of the pressure on the lefthand face of the large piston will permit the compressed air trappedbetween the two pistons to move the entire piston assembly to the left ashort distance. This causes the withdrawal of the rack 50 towards theleft (Fig. 3) and the rotation of shaft 5 in a clockwise direction. Thismovement of the shaft causes the door to open from four to six inchesthrough the connecting levers 6 and I. The person going through thedoorway continues to push on the plate I9 to finish the opening movementof the door which is a relatively simple operation now that the door hasbeen started open. As long as pressure continues on the plate, the largecylinder is open to exhaust and no resistance is offered by the engineto the opening of the door until 41 seats on 48. The final movement ofthe piston assembly is then retarded since the remainder of the air incylinder 22 is forced out through the restricted port 48. This insuresthat the final opening movement is retarded. The door may be held thelarge cylinder 3 with pipe ll.

open as long as desired by gently pushing on the plate 19 or pulling onthe doorknob 2|. 7

After the person has passed through the door and released the pushplate, a spring, not shown, such as is commonly used with such devices,swings it away from the door a. short distance to its normal positionallowing the switch l8 to return to its normal open position. Thisde-energizes solenoid 9 and valve l0 moves back to connect pipe II withpipe l6. To continue the descri tion, it will be first necessary to notethat when the door has been fully opened the piston assembly will havemoved to the extreme left in Figure 2 during a portion of which movementthe tube 40 will be stationary because the valve 41 has engaged the seat48. The final movement of the piston assembly will, therefore, compressspring 4| and also act to resiliently cushion the termination of thedoor opening movement.

Going back now to the connection of pipe II to l6, it will be seen thatair will be supplied into the left hand of the cylinder 22 through thepassage in member 40 around the ball valve 43. Air will also pass aroundthe ball valve 43 into the housing 33, and into cylinder 22 through theplus 39 around the member 40 as well a through port 49 in cap 25. Thepiston assembly continues its motion to the right until valve 41 openswhen the air directly enters cylinder 22 to complete the closing of thedoor and the'holding of it shut under pressure until the next operation.If for any reason the pressure between the pistons is lower than that incylinder 22, additional air will leak past the piston cup 3!, aspreviously .described, to equalize 1t and prepare the door for its nextopening movement.

The operation of the mechanism for holding the door open is no doubtclear from the foregoing description thereof but brief reference isagain made thereto. It will be recalled that the door can be heldopen-by continuing to push on the plate or bars II, but should one wishthe door to remain open while he is free to move about, heneedonlyushthedoortothepointwhere thecatch i'lisgrlppedbythearmsll. Thesesolenoid operator 9 energized and hence valve III operated, so that thelarge cylinder 3 is open to exhaust. Aside from any natural tendency ofthe door to close the mechanical catch need only be strong enough tohold the door against the effort of whatever air is trapped between thepistons that close'the door. These parts may be proportioned so thatwhen it is time to close the door a light pull on the door will releaseits catch from the spring pressed arms 59. At the same time switch 58will close, de-energizing the solenoid operator 9 so that valve 10 canreconnect The door will then close, as previously described.

From the above description it will be seen that the system hereindisclosed comprises an arrangement having all the desirable functions ofa door operating mechanism of this type. An important aspect of theinvention is that this operation is secured with an exceedingly simpleapparatus combination which differs from some equivalent system in thatrelatively few parts are required. of very simple construction. Thisapparatus is adapted to a long continued operation with littlemaintenance expenses and a minimum of possibility of disarrangement.Another advantage is that there is no danger of injury to persons usingthe door such as has been encountered in the past in the use of poweropened doors since most of the opening operation is accomplishedmanually.

Those skilled in the art will readily appreciate that considerablechanges in details of the mechanism herein disclosed can be made withoutdeparting from the novel subject matter herein disclosed. Forexample, inthe event that it is not thought necessary to cushion the final openingmovement of the door, this may be accomplished by eliminating thecushioning mechanism disclosed herein while still retainingsubstantially all or the advantages of the invention. 1 do not,

therefore, desire to be strictly limited by the disclosure herein givenfor purposes of illustration, but rather to the scope of the claimsgranted me.

What is claimed is:

l. A door operator comprising in combination a movably mounted door, adiflerential door engme connected to said door, means when energized forcontrolling the exhaust of pressure fluid from the large cylinder ofsaid engine and for supplying pressure fiuid to both cylinders whendeenergized, means for energizing said controlling means, whereby whensaid large cylinder is exnausted the air in the other cylinder operatesthe engine to open the door a short distance, means including amechanical latching device composed of a catch on the door and a keeperon an adjacent support Ior holding the door open, and means formaintaining the energization of the means for exhausting fluid pressurefrom the engine.

2, In the combination of claim 1, said means for energizing saidcontrolling means being mounted on the door.

3. In the combination of claim 1, said means for maintaining theenergization of the means ror exhausting pressure fluidirom the engineincluding circuits and a switch actuated by said catch for maintainingthe energiaatlon of the means for exhausting pressure fluid iron theengine, while the door is held open.

JOHN R. W

